In concert with the current trend of semiconductor devices toward higher density mounting and reductions of size, weight and profile, the number of wirings is increasing, requiring that the pitch between gold wires or between leads be finer. In concert with the higher performance speed of semiconductor devices, on the other hand, copper or copper alloy having good heat dissipation characteristics is mainly used as the lead frame material for suppressing the heat generation during operation.
For the advanced semiconductor devices, copper or copper alloy frames with fine pitch wiring become the main stream. These semiconductor devices are known to have the drawback that a short distance between leads causes a migration phenomenon to the copper used as the wiring or electrode, often resulting in electrical failures such as increased leakage current flow and short-circuiting between leads.
As used herein, the migration phenomenon means that moisture absorption causes the copper on the anode side of a semiconductor device to be ionized under an electric field, which results in dendritic precipitation of copper on the cathode side through redox reaction, detracting from insulation.
JP-A 11-092545 discloses an electronic component-encapsulating epoxy resin composition comprising an epoxy resin, a curing agent, and an inorganic filler.